A drawn arc stud weld on 2 mm plus base material is set with a 1/8 inch (3.18 mm) plunge past the ferrule, a lift of 1/16 to 1/8 inch (1.59 to 3.18 mm) scaling with stud diameter, and a controller-delivered weld time typically between 100 ms and 1500 ms [S1][S2][S4].
Plunge sets the volume of stud material available to form the fillet, while lift sets the air gap that creates the arc and the resistance heating; both are mechanical adjustments on the weld gun, not current or time settings, and they are checked before each shift with the stud against the plate and the trigger dry-cycled in the air [S2][S4].
Plunge depth: 1/8 in standard, 3/16 in on vertical walls
Plunge is defined as the length of stud that protrudes beyond the ceramic ferrule when the weld tool is in its rest position against the work [S2]. Two manufacturers give the same 1/8 inch (3.18 mm) starting value: Image Industries recommends "typically the amount of plunge should be set at 1/8 inch excluding the flux ball," while Haydon Bolts lists the same 1/8 to 3/16 inch (3.18 to 4.76 mm) past the ferrule as the correct set-up on all arc units [S2][S4][S5].
Vertical wall studding, where gravity works against fillet formation, calls for an additional 3/16 inch (4.76 mm) plunge to ensure complete fillet coverage [S2]. Plunge that is too short produces a thin or absent fillet (a "short plunge" defect), and plunge that is too long over-volumes the molten pool and creates splatter with an uneven, possibly incomplete fillet, since the extra travel also softens the spring forging pressure at the moment of plunge [S2][S4].
Lift height: diameter-scaled, 1/16 to 1/8 inch
Lift is the distance the stud is retracted from the plate after the trigger is pulled; it creates the air gap that the welding current bridges, and a zero lift is a direct short that will not develop the heat needed to melt the stud and parent material [S2]. The widely cited diameter-scaled table from Studwelding.ca maps stud base diameter to lift as: less than 1/2 inch (12.7 mm) stud at 1/16 inch (1.59 mm) lift, 1/2 to 3/4 inch (12.7 to 19.05 mm) stud at 3/32 inch (2.38 mm) lift, and greater than 3/4 inch (19.05 mm) stud at 7/64 inch (2.78 mm) lift [S4].
Image Industries extends the same range for general industrial work, recommending "a starting 3/32 inch lift and 1/8 inch plunge" and noting that structural applications, where larger diameter studs dominate, typically call for a 1/8 inch (3.18 mm) lift to keep the arc length stable against heavier thermal mass [S1]. The lift is set once and is not normally readjusted until the weld tool is disassembled, according to the Image Welder's Guide [S2].
How plunge and lift interact with current and time
Drawn arc is a four-variable process: current, time, lift, and plunge, and the variables are not independent in the field [S3]. Increasing lift raises arc length and resistance, which pushes the heat input up; an over-lifted arc goes "cold," producing a small, dull, uneven fillet with metal fingers pushing through the ferrule vents (the textbook cold-weld signature) [S2][S4]. A under-lifted arc goes "hot," giving a very shiny, low-profile fillet that extends beyond the ferrule outside diameter, indicating burn-off of stud material before plunge [S4].
Weld current is sized to stud diameter (roughly 600 to 3000 A across the 1/4 to 1 inch range common in arc studding) and weld time is set in milliseconds on the controller, with modern units such as the IWT LYNX Fusion offering 1 ms to 600 ms main weld time resolution to match heat input to stud size [S3][S7]. For reference, drawn arc is suited to base material 2 mm and thicker, can tolerate light rust, grease, and scale, and handles large-diameter studs that capacitor discharge cannot fuse, which is why it remains the default for shipbuilding, structural steel, and heavy fabrication [S3].
Gun set-up procedure and visual inspection
The mechanical procedure is: load the stud into the chuck, insert the ferrule into the ferrule grip, confirm the stud is centered with no contact against the ferrule during lift or plunge, and adjust the foot so 1/8 to 3/16 inch of stud protrudes past the ferrule end [S4]. To verify lift, the operator sets the timer to maximum, triggers the gun in the air (no contact with the plate), and measures how far the stud or mechanism travels; that distance is the actual lift, not the dial number [S4].
Visual inspection reads the fillet at the stud base, with five canonical outcomes: a good weld shows a full, even, shiny fillet all around; misalignment shows partial or no fillet and a stud out of perpendicular; short plunge shows no fillet and no stud burn-off; a hot weld is very shiny with a low fillet extending past the ferrule; a cold weld is small, dull, and uneven with metal fingers through the ferrule vents [S4]. If visual inspection leaves doubt, AWS-recommended destructive checks include the hammer or pipe-over-stud bend test (a good weld survives a 90 degree bend), torque test to a proof load, and tensile test to failure [S2][S4].
Comparison of plunge, lift, and current by stud diameter
Three diameter bands dominate the published tables and give a useful comparison for specification work [S1][S2][S4]:
Small studs (base diameter under 1/2 inch / 12.7 mm), general industrial work: plunge 1/8 inch (3.18 mm), lift 1/16 to 3/32 inch (1.59 to 2.38 mm), current roughly 600 to 1200 A, weld time 100 to 300 ms; result is a clean fillet sized for sheet-metal and light structural use [S1][S4].
Medium studs (1/2 to 3/4 inch / 12.7 to 19.05 mm), typical structural and shipbuilding use: plunge 1/8 inch (3.18 mm) on flat work, lift 3/32 inch (2.38 mm), current roughly 1200 to 2000 A, weld time 300 to 800 ms; on vertical walls, plunge steps up to 3/16 inch (4.76 mm) to compensate for gravity [S2][S4].
Large studs (over 3/4 inch / 19.05 mm and up to about 1 inch / 25.4 mm), heavy fabrication: plunge 1/8 inch (3.18 mm), lift 7/64 to 1/8 inch (2.78 to 3.18 mm), current 2000 to 3000 A, weld time 800 to 1500 ms, with controllers such as the Taylor i22 rated up to 22 mm stud diameter for these service conditions [S3][S4].
Common failure modes mapped to setting errors
Each visible defect in drawn arc traces back to a specific mechanical or electrical setting, and field engineers use the fillet signature to diagnose the dial rather than the gun [S2][S4]. A "hot" fillet (shiny, low, extending past the ferrule OD) means too much current, too long a time, or too little lift; cutting current by 10 to 15 percent or adding lift is the standard first move [S4].
A "cold" fillet (small, dull, with fingers through the ferrule vents) means too little current, too short a time, or too much lift; raising current or trimming lift back toward 1/16 inch on small studs is the fix [S2][S4]. A short-plunge or hang-up signature (no fillet, no burn-off) means the gun foot or chuck is binding so the stud is not reaching the molten pool, which is why the foot clearance and ferrule alignment are checked before the current is changed [S4]. Misalignment (no fillet on one side, stud not perpendicular) is a chuck or ferrule centering issue, not a setting issue, and is corrected by re-centering the foot, a step covered in any arc welder maintenance checklist. The choice of stud welding consumables, from the ferrule type to the stud material, also feeds back into the same lift and plunge numbers and should be locked before current and time are tuned.
Standards, sourcing, and signal nodes to watch
American Welding Society Chapter 9 of the Welding Handbook, Eighth Edition, Volume 2, edited by R.L. O'Brien (1991), remains the printed reference cited by Image Industries and other OEM training guides for the sequences, plunge, and lift conventions used in this article [S2]. Equipment-side, modern drawn arc controllers (Taylor i12, i16, i22, IWT LYNX Fusion) provide infinitely adjustable weld time and current with millisecond resolution, which lets the operator hold mechanical settings (lift, plunge) constant and trim only the electrical pair when the fillet signature drifts [S3][S7].
Two trackable signals for the next process-engineering review: first, drawn arc throughput on construction machinery and equipment and shipbuilding lines, where i22-class 22 mm-rated controllers are the new ceiling; second, any move by AWS or ISO to fold the 1/8 inch plunge / 1/16 to 1/8 inch lift convention into a written procedure-qualification record, since today it lives only in OEM welder's guides rather than a single normative table. For deeper background on how lift and plunge fit into the broader stud-welding process envelope, the drawn arc stud welding equipment reference page is the right starting point.
Closing note for shop-floor use: confirm the foot clearance and ferrule centering before every shift, dry-cycle the gun in the air to read the actual lift against the diameter-scaled table, set plunge to 1/8 inch on flat work and 3/16 inch on vertical walls, then trim current and time only against the fillet signature. If the fillet is shiny and low, reduce current; if it is dull and fingered, raise current or shorten the lift back toward 1/16 inch on small studs.
This topic is covered further in Die casting air purification: fume extraction specs, hood sizing, and 2026 selection.
